Hydraulic pump or motor



Feb. i939. E, K. @www 2,147,515

HYDRAULIC PUMP OR MOTOR Filed March 2e, 1936 4 sheets-sheet 1 n #al Feb. 14, 1939.v r E. K. BNEDEK 2,147,515

v HYDRAULIC PUMP -0R MOTOR Filed March 26, 1936 4 Sheets-Sheet 2 Feb. 14,1939. E, K. BENEDEKA v HYDRAULIC PUMP OR MOTORv Filed March 26, 1936 4 Sheets-Sheet 3 Feb. 14, 1939.

E. K. BENEDl-:K- I 2,147,515 HYDRAULIC PUMP 0R MOTOR Filed March A26, 1936 4 vsheets-shem- 4 Patented Feb. 14, 1939- UNITED STATES PATENT OFFICE HYDRAULIC PUMP on Moron.

Elek K. Benedek, Bucyrus, 0h10 Application March 2s, 1936, sei-iai No. '11,005

1 claim. (ol. 10s- 161)y i This invention relates to hydraulic pumps or motors and more particularly to hydraulic pumps or motors of the kind comprisingl a plurality of radial piston and cylinder assemblies mounted for rotation about a pintle 'or the like. Pumps or motors of this general class or description are well known in the art and may be of either the fixed or variable discharge type. As will be understood from the description which follows, improvements in accordance with my present invention may bev embodied in pumps or motors of this general class, whether they be of the fixed or variable discharge type.-

Due to the high pressure working conditions usually prevalent, there is considerable heating of the pressure fluid, and consequently appreciable heating and expansion of thepump or motor parts. A fundamental requirement for eiiicient operation is themaintaining of accurately predetermined clearances, particularly between the cylinder barrel and the pintle about which it rotates. Inmost such pumps, the cylinder barrel and pintle are formed with ports which c0- operate to effect the necessary valving of the ow to and from the cylinders. Hence, if the clearance between the cylinder barrel and the pintle is allowed to become too large, due to expansion of one or both of the elements, or to any other cause, there will be a pressure loss directly diminishing the capacity of the machine and producing other undesirable results such as noisy and vibratory operation. On the other hand, if the clearance is made toosmall, it will not be possible to maintain the oil film necessary for quiet running and efficient operation. The maintaining of just the correct amount of `clearance therefor is very important.

An object of the present invention is to provide an improved pump or motor structure including bearings supporting the cylinder barrel with respect to the pintle and the casing in a novel manner resulting in smoother and more eliicient operation and longer life than other pumps or mo- Vtors of the class referred to.

Another object is to provide an improved pump or motor structure in which the clearance between the cylinder barrel and the pintle may be maintained substantially constant, irrespective of unequal expansion or contraction of different parts. Other objects will become apparent from a reading of the -following description, the appended claim, and the accompanying drawings, in which:

Figure 1 is an axial section of a pump or motor embodying the invention. Figure 2 is a similar view showing the invention embodied in a somewhat different form. Figure 3 is a similar lview-showing the invention embodied in still a different form. Figure 4 is a transverse section taken on the line 4-4 of -Figure 1. Figure 5 is a diagrammatic view illustrating schematically one principle of embodiment of the invention, and Figure 6 is a diagrammatic view illustrating schematically a. slightly different principle of embodiment. v l

One structure embodying the invention in prac. tical form is shown in Figures 1 and 4 as including a casing A, a xed cantilever pintle B, a cylinder barrel C mounted for rotation about the pintle, a plurality of radially disposed pistons D, and means generally designated E for effecting reciprocation of the pistons within theassociated cylinder bores in the barrel C. -The structure will be described as a pump but it will be understood that it may function as a motor also.

'I'he mounting and supporting of the cylinder barrel for rotation about the xed pintle in accordance with the invention claimed in this application will be described later. Attention first will be directed to the general structural organization of parts not claimed in this application, but an understanding of which will be required in order to render fully apparentthe features herein described as constituting the invention claimed in this application. The casing A comprises separable sections I'and 2 secured together by means of bolts 3. The reaction means E comprises rings 4-4 secured together by means of bolts 5 and maintained in properly spaced relation by spacers 6. Heads. Iia on the pistons are connected in driving relation to the rings 4--4 lby pins 1 mounted in the heads by anti-friction bearings 8 and having reduced end portions projecting into opposed track grooves formed in the rings 4-4. Anti-friction bearings 9 mount the ring assembly 4-4 within an outer reaction ring I0 which isv supported for shifting movements by means of rods Il passing through apertures in the casing and by pads I2 on the ring l0 ywhich are mounted for sliding movement on pads I3 on the casing. As is well understood in the art, when the cylinder barrel is rotated with the reaction means E in an eccentric position relative to the pintle, the pistons D will be caused to reciprocate within their respectively associated cylinders I4. The cylinders communicate vby means of ports I5 with cooperating valve ports I6 in the pintle for valving the flow of fluid to and from the cylinders in a manner well known in the art. v

In accordance with the invention claimed in this application, the cylinder barrel C shown in Figures 1 and 4 is supported in a novel manner permitting axial expansion relatively between the casing and the pintle or the cylinder barrel without disturbing the desired close clearances and at the same time there being no appreciable play or looseness in the bearing parts supporting the cylinder barrel with respect toradial loads or stresses. In the form shown by way of illustra-V tion in Figures 1 and 4, the pintle-B includes a cylindrical anchoring portion I1 which has a press ilt or is otherwise securely ixed within a bore I8 inthe casing section I, the pintle being formed with a flange I9 abutting against the casing section I at the inner end of the bore I8 for locating the pintle properly. Beyond the flange I9 the pintle includes a cylindrical bearing portion 20, a tapered portion 2 I, and an outer cylindrical bearing portion 22.

It will be understood that it is desirable to maintain a very close running ilt between the tapered portion2| of the pintle and the associated cooperating tapered bore of the cylinder barrel. This is desirable in order to provide for the formation of an oil film between the tapered portion 2I and the cylinder barrel,'thus providing for effective sealing of the fluid. Obviously, if the clearance is. too large, fluid will leak along the pintle resulting in a pressure loss. hand, if the clearance is too small there is danger that the parts will have rubbing metal-to-metal contact resulting in scoring and damaging of either the pintle or the cylinder barrel or both. Therefore, in accordance with my invention I so connect the cylinder barrel and pintle as to maintain a substantially fixed desirable clearance and yet to permit axial expansion of these parts such as would be due to heating of the fluid. To this end I provide bearings between the pintle and the cylinder barrel at both ends of the latter, the bearings at at least one end being so arranged as to constrain that end of the pintle to move axially together with the associated end of the cylinder barrel. As shown, the inner end of the cylinder barrel, i. e., that nearest the fixed end of the pintle, is supported for rotation about the latter by an anti-friction bearing 23 which comprises an inner race 24 surrounding the bearing portion 20 of the pintle and an outer race 25 tting within a counterbore 26 in the cylinder barrel. At the outer or free end of the pintle there is provided an antlfrlction bearing 21 comprising an inner race 28 surrounding the bearing portion 22 of the pintle .and clamped between a shoulder 29.and a` Washer 30 drawn up by a nut 3|; and an outer race 32 located within a counter-bore 33 in the cylinder barrel. A drive shaft 34 is connected to the cylinder barrel by means of a coupling Bange 35 secured to the cylinder barrel by bolts 38 thev -shaft thereby in effect constituting a part of the cylinder barrel. An annular rib 31 on this coupling flange engages the outer bearing race 32 and locks the latter in the counter-bore 33. It will be observed that there can be no relative axial movement between the cylinder barrel and the outer or free end of the pintle. However, I have provided for simultaneous or conjoint axial movement of the barrel and pintle in order to permit expansion of the parts by causes such as ,heating The expansion is provided for by mounting the drive shaft within the casing by abearing arrangement which, in the form shown, comprises an inner race 38 clamped against a shoulder 38 by lmeans of a nut 40, the race being grooved peripherally for the reception of rollers 4I which are surrounded by and in engagement On the other It is apparent that expansion of the pintle and cylinder barrel or casing in an axial direction due to heating or other causes can take place readily without disturbing any of the essential clearances and without requiring any looseness of the bearings transmitting radial stresses. This results in elimination of vibration and pressure loss due to fluid slip or leakage, and ln more quiet and eileient operation'oi the pump as a Whole.

Figure 2 shows a pump or motor embodying the invention in principle similar to the pump or motor shown in Figure l, but differing as to certain specific details. In the Figure 2 form, all the parts are similar to corresponding parts in the Figurev 1 form with the exception of the bearings interposed between the pintle and the cylinder barrel, which bearings differ in some specific respects. Therefore, in Figure 2, the parts which are the same as corresponding parts in Figure 1 are designated by reference characters` which are the same as those applied to corresponding parts in Figure 1 with the exception that such reference characters in Figure 2 are primed. Thus, the casing sections I and 2' of. Figure 2 correspond to the casing sections I o and 2 of Figure 1. Similarly, the reaction rings 44 of Figure 2 correspond to the reaction rings 4 4 of Figure l.

The difference of the Figure 2 form over that shown in Figure l resides in the provision of tapered roller bearings in place of the ball bearings for supporting the cylinder barrel on the pintle. In the Figure 2 form an inner race 4l is mounted on the cylindrical bearing portion 28 of the pintle I'l' and is provided with an inclined groove 48 which receives roller bearings 49. An outer race 50 is formed with an inclined bearing face 5I cooperating with the rollers 49 and is mounted within the counter-bore 25 in the cylinder barrel. At the outer end of the pintle an inner race 52 is clamped between the shoulder 28 andthe washer 30 and is provided .with anA inclined groove 53 which receives roller bearings 54. An outer race 55 formed with an inclined face 56 is positioned within the counter-bore 33 in the cylinder barrel. The bearing for mount- .ing the drive shaft 34' and, consequently, the' cylinder barrel within the casing comprises parts 38', 39', 40', etc. which correspond to and are the same as parts 38, 39 and 40 described with It will be observed that constructions embodying thev claimed inventionA make it possible and desirable to provide initially and to maintain snugly fitting bearings for transmitting radial stresses.

Figure 5 shows schematicallyI the principle underlying the invention as embodied in the forms shown in Figures 1 and 2. Thus, the casing or xed pump Apart is' designated lc, the

pintle. l, the cylinder barrel m, the bearings between the cylinder barrel and the pintle n, and the bearing between the cylinder barrel and the casing, o. From a. consideration of Figure 5, it is apparent that the invention may be embodied in pumps having straight or non-tapered pintles as Well as in those in which the pintle is tapered. However, the functional advantages resulting from bearing arrangements in accordance with my invention are Ymore outstanding in pumps including tapered pintles.

Figure 3 shows an embodiment of the invention in which the cylinder barrel is so mounted within the casing as to be constrained against bodily axial movement with respect to the casing but is supported on the pintle in such manner as to permit a small amount of relative movement axially with respect to the pintle. The arrange ment is such as to permit this small movement between the pintle and cylinder barrel without its being necessary to provide any appreciable radial rlooseness or play in the bearings. The pump shown in Figure 3 includes a casing A", a pintle B", cylinder barrel C", a plurality of radially disposed cylinders D",` and reaction means generally designated E for effecting reciprocation of the pistons. The pump casing includes sections I" and 2 secured together by means of bolts 3". The reaction means E" includes inner reaction rings 4 secured together by means of bolts 5V" and maintained in spaced relation by means of spacers 6". Pins 1" mounted in the piston heads by means oi antifriction Vbearings 8 are provided with reduced end portions which project intol annular track grooves conjointly formed by the rings l" and associated inside track ring members IV-IV.y

Anti-friction bearings 9" mount the rings 4 within an outer reaction ring I" supported forv shifting movements by means of rods I I passingV through the casing section I". The pistonsl D f' are mounted for reciprocation incylinders I4" in the cylinder barrel C" andcommunicate with ports I" adapted vto coactwith pintle ports I6" for valving the flow o iluid.V

The pintle B" is provided with a cylindrical anchoring part I1" having a press nt or being otherwise securely mounted within a bore I8" X in the casing half I". Beyond the anchoring portion the pintle is formed with a cylindrical bearing portion 2li", a tapered portion ZI", and an outer cylindrical bearing portion 22".

A A roller bearing assembly 23 is mounted adjacent theinner end of the'pintle with its inner race 24" surrounding the cylindrical bearing portion of the pintle and being grooved for the rollers. The outer race 25 likewise is grooved for reception of the rollers and is mounted within a counter-bore 26" injthe cylinder barrel. It will be observed that the races 2l and 25" are adapted to have a smalljamount of-sliding Inovement with respect to the pintle and the cylinder barrel, respectively. f

A roller bearing assembly 2-1l located adjacent the outer end of the pintlehasits inner race 28" surrounding the cylindrical portion 22" of the pintle and clamped betweena shoulder 29 von the pintle and'a washer 130" drawnupby a nut The yinner racevl ,is provided :with a groove for receiving therollers as is alsothe -outer race 32" whichis positioned Vwithin a counter-bore 33" inthe cylinder barrel.Y The outer race is so positioned as to be movable to a limited extent axially with respect to the cylinder barrel.

y In this embodiment ofthe invention,'thedrive shaftv and .cylinder barrel areso mounted as to be constrained against bodily/axial' movement with respect to-the casing. Asfshown, the'drive shaft 3l" is provided with; a coupling ilange 35" secured to the cylinderbarrellby means-ofbolts 36", and is held centered with respect to Athe latter by means of an annularribl". The-shaft changes in the specific ment of the parts may be made without departing v inder barrel against both axial ing devices comprising 34" and, consequently, the cylinder barrel are maintained against radial and axial movements with respect to the casing by means of an antiiriction bearing including a race 38" clamped against a shoulder 39" of the shaft by means of a nut 40" and grooved for the reception of ball elements 4I". An outer race likewise grooved for the reception of the ball elements is clamped against a shoulder 43 a rib 44" on a cap member 45". Thus, no bodilyv axial shift or movementvof the shaft and cylinder barrel can take place. However, as previou'sly stated, the bearings between the pintle and the cylinder barrel are such as to permit slight relative axial movement'therebetween in order to provide for unequal expansion. of the parts.

The principle underlying this embodiment of the invention is shown schematically in Figure 6, in which lc" indicates the casing, l" the pintle, m" the cylinder barrel, n" the bearings between the pintle and cylinder barrel at the opposite ends of the pintle, and o" the bearing between the cylinder barrel and the casing whichy constrains the cylinder barrel against both axial and radial movements relative to a consideration of this ilgure, it will be apparent that advantages resulting from the present invention may be obtained in pumps or motors including a straight or cylindrical pintle as well as in pumps or motors equipped with tapered pintles.

It will be understood illustrative of other forms and that various construction and arrangeirom the invention as I claim:

In a hydraulic pump or motor, the combination of a casing having iirst and second side walls and an annular wall integral with said ilrst side wall, a tapered cantilever pintle rigidly secured to said first side wall and extending into said casing, a cylinder barrelmounted for rotation about said pintle, a drive shaft aligned with saidpintle, an anti-friction bearing assembly interposed between said drive shaft and sai second side vwall and comprising a race secured tp the second-side wall of the casing,

defined in the claim.

a race secured to the drive shaft, interposed bearing elementsl constructed to cooperate with said races to constrain said Acyland radial movements relative to the casing, said cylinder barrel having a recess in each end, anti-friction devices disposed in said recesses mounted directly on the pintle and surrounded by and supporting the cylinder barrel on the pintle at both end s and maintaining positive clearance between the barrel and the pintle and constraining them to relative axial movement such as would :be due to expansion and contraction, saidranti-friction bearinner and outer races and interposed rolling elements, one of said races being movable axially relatively to the part other than the rolling elements with which lt is in contact, said drive shaft closing one of said recesses and having anange securedto the adjacent end `oi? the cylinder barrel,` reactance means and a mns: x. Bananes.

the casing. From that the embodiments of my invention disclosed herein are genericallyv 

